1. Field of the Invention
The invention is directed to an internal combustion engine having a plurality of combustion cylinders at each of which a fuel injection device is provided and having at least one fuel pump for supplying a predetermined fuel pressure. An internal combustion engine of the type mentioned above can be outfitted with a common rail fuel system whose components comprise a fuel pump, fuel pressure accumulator or fuel accumulator, fuel injection devices or fuel injectors, and fuel lines.
2. Description of the Related Art
In some internal combustion engines, particularly in medium-speed diesel engines, it is useful for reasons pertaining to design, manufacture and logistics to divide the fuel accumulator into a plurality of small fuel accumulators instead of providing a single fuel accumulator along the entire length of the engine and connecting this plurality of fuel accumulators to one another by means of fuel lines. The fuel pressure can be generated by a plurality of fuel pumps (e.g., high-pressure pumps) arranged on a pump bank.
Internal combustion engines with a common rail fuel system are described in DE 101 57 135 B4 and EP 0 959 245 B1. In these internal combustion engines, principally two combustion cylinders are supplied with fuel from a fuel pressure accumulator. Thus, when there is an odd number of cylinders a fuel pressure accumulator must be provided for supplying fuel to only one individual combustion cylinder. Further, since these common rail fuel systems are formed of a plurality of separate (high-pressure) fuel pumps and fuel pressure accumulators, they require a large number of fuel lines which are designed for high pressure and which have different deflection curves and lengths, which increases production costs and makes it more difficult to provide replacement parts.
In view of the fact that the fuel pumps in the common rail fuel systems described in the above-cited documents deliver fuel into the fuel pressure accumulators via one or two fuel lines designed for high pressure, each fuel line itself represents a choke point. This leads to high pressure peaks in the fuel pump connected thereto. Accordingly, the risk of overloading of component parts and leakiness at high-pressure seals increases. The intermittent delivery of the fuel pumps leads to a massive excitation of vibrations in the fuel lines leading from the fuel pumps. This increases the risk of line breakage due to fretting or friction wear at the fastening points as a result of the high vibrational stress.